Marshall dann

ABSTRACT

1. A DEWAXING PROCESS FOR THE SELECTIVE CRACKING OF STRAIGHT-CHAIN HYDROCARBONS AND SLIGHTLY BRANCHED-CHAIN HYDROCARBONS FROM A MIXTURE OF THE SAME WITH COMPOUNDS OF DIFFERENT MOLECULAR SHAPES WHICH COMPRISES CONTACTING SAID MIXTURE WITH A CRYSTALLINE ALUMINOSILICATE HAVING AN X-RAY DIFFRACTION PATTERN AS SET FORTH IN TABLE 1 AND HAVING PORE OPENINGS WHICH ARE OF A GENERALLY ELLIPTICAL SHAPE WHEREIN THE MAJOR AXIS OF SAID ELLIPSE HAS AN EFFECTIVE SIZE UNDER CONVERSION CONDITIONS OF BETWEEN ABOUT 6 AND 9A. UNITS AND THE MINOR AXIS ABOUT 5 A. SO THAT SAID STRAIGHT-CHAIN AND SLIGHTLY BRANCHEDCHAIN HYDROCARBONS ARE CAPABLE OF ENTERING INTO THE INTERNAL PORE STRUCTURE OF THE ALUMINOSILICATE AND BEING CONVERTED, SAID ALUMINOSILICATE HAVING A COMPOSITION, IN TERMS OF OXIDE MOLE RATIOS, AS FOLLOWS:   0.9$0.2 M2/NO:AL2O3:5-100 SIO2:ZH2O   WHEREIN M IS A CATION, N IS THE VALENCE OF SAID CATION AND Z IS FROM 0 TO 40.

United States Patent Re. 28,398 Reissued Apr. 22, 1975 Matter enclosedin heavy brackets If] appears in the original patent but forms no partof this reissue specification; matter printed in italics indicates theadditions made by reissue.

ABSTRACT OF THE DISCLOSURE Straight-chain hydrocarbons and slightlybranchedchain hydrocarbons are selectively converted utilizing novelcrystalline zeolites having unique molecular sieving properties. Thecatalyst preferably contains acidic cations and can also contain acomponent having a hydrogenation/dehydrogenation function. The processof this invention is particularly useful for the dewaxing of hydrocarbonoils including removal of high freezing point paraffins from jet fuel tolower freezing point, as well as improving the octane rating of naphthafractions.

RELATED APPLICATIONS This application is related to application Ser. No.865,- 472, filed Oct. 10, 1969, and application Ser. No. 865,- 418,filed Oct. 10, 1969, which are directed to ZSM-S and ZSM8 typealuminosilicates respectively.

BACKGROUND OF THE INVENTION (1) Field of the invention This inventionrelates to novel dewaxing processes carried out in the presence ofcrystalline zeolitic material and, more particularly, to the removal ofstraight-chain parafiins and slightly branched-chain paraffins fromhydrocarbon feedstocks by selectively converting these materials from amixture of the same with the other components generally found inhydrocarbon feedstocks.

(2) Description of the prior art Hydrocarbon conversion processesutilizing crystalline zeolites and, in particular, aluminosilicatecatalysts have been the subject of extensive investigation during recentyears as is obvious from both the patent and scientific literature.Crystalline aluminosilicates have been found to be particularlyeffective for a wide variety of hydrocarbon conversion processes andhave been described and claimed in many patents including US. Pats.3,140,249; 3,140,252; 3,140,251; 3,140,253; and 3,271,418. Aside fromserving as general catalysts in hydrocarbon conversion processes, it isalso known that the molecular sieve properties of zeolites can beutilized to preferentially convert one molecular species from a mixtureof the same with other species.

In a process of this type a zeolite molecular sieve is employed havingcatalytic activity within its internal pore structure and pore openingssuch that one component of a feed is capable of entering within theinternal pore structure thereof and being converted to the substantialexclusion of another component which, because of its size, is incapableof entering within the pores of the zeolitic material. Shape selectivecatalytic conversion is also known in the art and is disclosed andclaimed in US. Pats. 3,140,- 322; 3,379,640 and 3,395,094.

Although a wide variety of zeolitic materials and particularlycrystalline alurninosilicates have been successfully employed in variouscatalytic conversion processes, nevertheless, these prior art processes,in general, fell into one or two main categories. In one type ofconversion process a zeolite was employed which had a pore sizesufficiently large to admit the vast majority of components normallyfound in a charge, i.e., these materials are referred to as large poresize molecular sieves and they are generally stated to have a pore sizeof from 6 to 13 angstroms and are represented by zeolites X, Y and L.The other type of aluminosilicate was one which had a pore size ofapproximately 5 angstrom units and it was utilized to preferentially actupon normal parafiins to the substantial exclusion of other molecularspecies. Thus, by way of considerable over-simplification up until thepresent invention, there were only two types of aluminosilicates whichwere available for hydrocarbon processing those which would admit onlynormal parafiins and those which would admit all components normallypresent in a hydrocarbon feed charge.

DESCRIPTION OF THE INVENTION It has now been discovered that veryeifective catalytic operations can be carried out by utilizing a classof zeolitic molecular sieves which possess unique sieving properties inthat they allow entry and egress to their internal pore structure of notonly normal paraflins but also of slightly branched parafiins, and yethave the ability to exclude heavily branched isoparaflins. Thus, it isnow possible to carry out hydrocarbon conversion processes which are notonly selective towards normal parafiins, but also are selective towardsslightly branched paraflins and, in particular, monomethyl-substitutedpar-afiins. It has now been discovered that when zeolitic materialsexhibiting these properties are employed in those dewaxing operationswhere it has been heretofore desirous only to selectively remove normalparafiins that many increased and unexpected benefits will occur in thatthe resulting products have enhanced economic value.

As has heretofore been stated, all the crystalline aluminosilicatematerials heretofore employed in prior art processes fell into one oftwo general types. They either have pore sizes of about 5 angstrom unitsor have pore sizes from about 6 to about 15 angstrom units. The 5angstrom unit aluminosilicates were generally stated to be shapeselective in that they allowed selective conversion of normal aliphaticcompounds from a mixture of the same with isoaliphatic compounds andcyclic compounds. The second type of aluminosilicate, i.e., those havinga pore size of 6 to 15 angstrom units were generally stated to benonselective, i.e., substantially all of the molecules normally found ina hydrocarbon feed stream are able to enter within the internal porestructure of the zeolites and be converted. Thus, heretofore a veryconvenient method of identifying a good shape selective catalyst was toshow that it would selectively crack normal hexane from a mixture of thesame with 2-methyl pentane since the former was able to enter itsinternal pore structure, whereas the latter isocompound was unable to doso.

The novel dewaxing process of this invention is predicated upon usingzeolitic materials which can generally be stated to be intermediatebetween the two types of aluminosilicates heretofore employed. Thus,catalysts of this invention will allow the entry into their internalpore structure of normal aliphatic compounds and slightly branchedaliphatic compounds, particularly monomethylsubstituted compounds, yetsubstantially exclude all compounds containing at least a quaternarycarbon atom or having a molecular dimension equal to or substantiallygreater than a quaternary carbon atom. Additionally, aromatic compoundshaving side chains similar to the normal aliphatic compounds andslightly branched aliphatic compounds above described could have saidside chains enter the internal pore structure of the instant catalysts.Thus, if one were to measure the selectivity of the zeolitic materialsemployed in the processes of this invention by the heretofore mentionedprior art tests, i.e., the ability to selectively crack hexane from amixture of the same with isohexane, these catalysts would have to bestated as being non-shape selective. It should be immediately apparent,however, that the term selectivity has a far greater significance thanmerely the ability to preferentially distinguish between normalparaflins and isoparafiins. Selectivity on shape is theoreticallypossible at any shape or size although, quite obviously, suchselectivity might not result in an advantageous catalyst for any and allhydrocarbon conversion processes.

The novel dewaxing processes of this invention are based upon the factthat, although it is art-recognized that in the vast majority ofrefinery operations it is desirous to preserve aromatics and to removenormal paraflins, nevertheless, such a generalization is not the finalword in obtaining maximum yields of economically enhanced products. Ithas now been discovered that enhanced benefits can be obtained if acatalyst system could be designed which would not only selectivelyconvert normal paraffins, but certain isoparaffins, and yet not affectdesirable components in a given feedstock. This type of molecularprocessing or sieving was heretofore unknown. As has been stated, allthe previous catalytic processing involving the use of zeoliticmolecular sieves merely gave the operator two choices. He could eitheruse a molecular sieve which was a catalyst of generalized competence,i.e., it would act upon substantially all of the molecules normallyfound in a hydrocarbon feed or he could use a catalyst which had a poresize of about 5 angstrom units thereby allowing selective conversion ofnormal aliphatic compounds only.

While not wishing to be bound by any theory of operation, nevertheless,it appears that the crystalline zeolitic materials employed in theinstant invention cannot simply be characterized by the recitation of apore size or a range of pore sizes. It would appear that the uniformpore openings of this new type of zeolite are not circular in nature, asis usually the case in the heretofore employed zeolites, but rather, areelliptical in nature. Thus, the pore openings of the instant zeoliticmaterials have both a major and a minor axes, and it is for this reasonthat the unusual and novel molecular sieving effects are achieved. Thiselliptical shape can be referred to as a keyhole. It would appear thatthe minor axis of the elliptical pores in the zeolites apparently havean effective size of about 5.5 angstrom units. The major axis appears tolie somewhere between 6 and about 9 angstrom units. The unique keyholemolecular sieving action of these materials is presumably due to thepresence of these elliptically shaped windows controlling access to theinternal crystalline pore structure.

A test method has been devised in order to determine whether or not azeolite possesses the unique molecular sieving properties necessary tocarry out the novel conversion process of this invention. In said testmethod a candidate zeolite free from any matrix or binder is initiallyconverted to the so-called acid or hydrogen form. This procedureinvolves exhaustive exchange with an ammonium chloride solution in orderto replace any metallic cations originally present. The sample is thensized to 20-30 mesh and calcined in air for 16 hours at 550 C. One gramof the so-treated zeolite is then contacted with benzene at a pressureof twelve torr at a temperature of 25 C. for a time period of two hours.Another gram sample is contacted with mesitylene at a pressure of 05torr at a temperature of 25 C. for a period of six hours. An operablezeolite is one whose acid form will absorb at least 3.0 weight percentbenzene and less than 1.5 Weight percent mesitylene at the above recitedconditions.

Examples of zeolitic materials which are operable in the process of thisinvention are ZSM-S type and ZSM-8 type zeolites. ZSM-S type materialsare disclosed and claimed in copending application Ser. No. 865,472filed Oct. 10, 1969 and ZSM-8 is disclosed and claimed in copendingapplication Ser. No. 865,418, filed Oct. 10, 1969.

The family of ZSM5 compositions has the characteristic X-ray diffractionpattern set forth in Table 1, hereinbelow. ZSM5 compositions can also beidentified in terms of mole ratios of oxides, as follows:

wherein M is a cation, n is the valence of said cation, W is selectedfrom the group consisting of aluminum and gallium, Y is selected fromthe group consisting of silicon and germanium, and z is from 0 to 40. Ina preferred synthesized form, the zeolite has a formula, in terms ofmole raios of oxides, as follows:

and M is selected from the group consisting of a mixture of alkali metalcations, especaially sodium, and tetraalkylammonium cations, the alkylgroups of which preferably contain 2-5 carbon atoms.

In a preferred embodiment of ZSM-5, W is aluminum Y is silicon and thesilica/alumina mole ratio is at least 10 and ranges up to about 60.

Members of the family of ZSM5 zeolites possess a definite distinguishingcrystalline structure whose X-ray diffraction pattern shows thefollowing significant lines:

TABLE 1 Interplanar spacing d(A): Relative intensity 11.110.2 S 10.0102S 7.410.15 W 7.110.15 W 6310.1 W 6.0410 1 W 59710.1 W 5 5610.1 W 50110.1 W 4.601008 W 42510.08 W 3.851007 VS 3.711005 S 3.641005 M3.041003 W These values as well as all other X-ray data were determinedby standard techniques. The radiation was the K-alpha doublet of copper,and a scintillation counter spectrometer with a strip chart pen recorderwas used. The peak heights, I, and the positions as a function of 2times theta, where theta is the Bragg angle, were read from thespectrometer chart. From these, the relative intensities, I/I where I isthe intensity of positions as a function of 2 times theta, where thetais the Bragg angle, were read from the spectrometer chart. From these,the relative intensities, 100 I/I where I is the intensity of thestrongest line or peak, and d (obs), the interplanar spacing in A,corresponding to the recorded lines, were calculated. In Table 1 therelative intensities are given in terms of the symbols S:strong,M=medium, MS=medium strong, MW=medium weak and VS=very strong. It shouldbe understood that this X-ray diffraction pattern is characteristic ofall the species of ZSM-5 compositions. Ion exchange of the sodium ionwith cations reveals substantially the same pattern with some minorshifts in interplanar spacing and variation in relative intensity. Otherminor variations can occur depending on the silicon to aluminum ratio ofthe particular sample, as well as if it has been subjected to thermaltreatment. Various cation exchanged forms of ZSM 5 have been prepared.X-ray powder diffraction patterns of several of these forms are setforth below. The ZSM-5 forms set forth below are all alunlinosilicates.

TABLE 2.X-RAY DIFFRACTION ZSM-5 Powder in Cation Exchanged Forms (1Spacings Deserved As made H01 NaCl CaCh ReCla AgNO 7. 46 7. 11 6. 6.375. 99 5.70 5. 57 5. 37 5. 14 5. 12 5. 01 5.01 4. 74 4. 62 4. til 4. 4.46 4. 46 4. 4. 37 4. 36 4. 4. 27 4. 26 4. 4.09 4. 09 4. 4.01 4. 00 4. 3.3. 3. 85 3. 3 3. 82 3. 82 3. 82 3. 3. 3. 75 3. 75 3. 76 3. 3.7 3.72 3.723.72 3. 3.6 3. 65 3. 65 3. 65 3. 65 3. 65 3. 60 3. 60 3. 6|) 3. 61 3.[10 3.48 3. 49 3. 49 3. 48 3. 49 3. 49 3.44 3. 45 3. 45 3. 44 3. 45 3.45 3.34 3. 35 3. 36 3. 35 3. 35 3. 35 3.31 3. 31 3. 32 3. 31 3. 32 3. 323.25 3. 25 3. 26 3. 25 3.25 3 26 3.17 3.17 3.18 3.13 3. 14 3.14 3.14 3.15 3.14 3.05 3.05 3.05 3. 04 3. O6 3. 05 2.98 2. 98 2. 99 2. 98 99 2 99.97 2. 2. 95 2 E15 2.87 2. 87 2 S7 WWW woman-2 Zeolite ZSM5 can besuitably prepared by preparing a solution containing tetrapropylammonium hydroxide, sodium oxide, an oxide of aluminum or gallium, anoxide of silica or germanium, and water and having a composition, interms of mole ratios of oxides, falling within the following ranges:

wherein R is propyl, W is aluminum or gallium and Y is silicon orgermanium maintaining the mixture until crystals of the zeolite areformed. Thereafter, the crystals are separated from the liquid andrecovered. Typical reaction conditions consist of heating the foregoingreaction mixture to a temperature of from about C. to 175 C. for aperiod of time of from about six hours to 60 days. A more preferredtemperature range is from about to C. with the amount of time at atemperature in such range being from about 12 hours to 8 days.

The digestion of the gel particles is carried out until crystals form.The solid product is separated from the reaction medium, as by coolingthe whole to room temperature, filtering, and water washing.

The foregoing product is dried, e.g., at 230 F., for from about 8 to 24hours. Of course, milder conditions may be employed if desired, e.g.,room temperature under vacuum.

ZSM-S is preferably formed as an aluminosilicate. The composition can beprepared utilizing materials which supply the appropriate oxide. Suchcompositions include for an aluminosilicate, sodium aluminate, alumi na,sodium silicate, silica hydrosol, silica gel, silicic acid, sodiumhydroxide and tetrapropylammonium hydroxide. It will be understood thateach oxide component utilized in the reaction mixture for preparing amember of the ZSM5 family can be supplied by one or more initialreactants and they can be mixed together in any order. For example,sodium oxide can be supplied by an aqueous solution of sodium hydroxide,or by an aqueous solution of sodium silicate; tetrapropylammonium cationcan be supplied by the bromide salt. The reaction mixture can beprepared either batchwise or continuously. Crystal size andcrystallization time of the ZSM-5 composition will vary with the natureof the reaction mixture employed. ZSM8 can also be identified, in termsof mole ratios of oxides, as follows:

0.9i0.2 M OzAl o 5-100 SiO :zH O

wherein M is at least one cation, n is the valence thereof and z is from0 to 40. In a preferred synthesized form, the zeolite has a formula, interms of mole ratios of oxides, as follows:

M2 0IAl203: SlOgiZHgO and M is selected from the group consisting of amixture of alkali metal cations, especially sodium, andtetraethylammonium cations.

[ZSM-8 possesses a definite distinguishing crystalline structure havingthe following X-ray diffraction pattern:

TABLE 4 I/In 1111. 1/19 rlA. I/In (IA. I/I

4.35 7 3.04 10 2.32 l 4.25...." 18 2.119. 0 2.28 1 4.07 20 2.07- 4 2.231 4.00 10 2.04. 3 2.20 1 3.85 100 2.80- 2 2.17 1 3.82 57 2.78. 1 2.1 13.75 2.5 2.73. 4 2.11.. 1 3.71 30 2.08. 1 2.08- 1 3.04 26 2.61. 3 2.06..1 3.50. 2 2.57 1 2.01- B 3.47 0 2.55- 1 1.00. 6 3.43 0 2.51. 1 1.05 23.3L] 5 2.49. 0 1.91. 2 3.3 1 18 2.45. 1 1.87- 3 3.31 8 2.47- 2 1.84. 1324...-.- 4 2.39- 3 1.82 2 3.13 3 2.35 1

Zeolite ZSM-8 can be suitably prepared by reacting a solution containingeither tetraethylamrnonium hydrazide or tetraethylammonium bromidetogether with sodium oxide, aluminum oxide, and an oxide of silica andwater.

The relative operable proportions of the various ingredients have notbeen fully determined and it is to be immediately understood that notany and all proportions of reactants will operate to produce the desiredzeolite. In fact, completely different zeolites can be preparedutilizing the same starting materials depending upon their relativeconcentration and reaction conditions as is set forth in United States3,308,069. In general, however, it has been found that whentetraethylammoniurn hydroxide is employed, ZSM-S can be prepared fromsaid hydroxide, sodium oxide, aluminum oxide. silica and water byreacting said materials in such proportions that the forming solutionhas a composition in terms of mole ratios of oxides falling within thefollowing range.

SiO /Al O from about 10 to about 200 Na O/tetraethylammoniumhydroxide-from about 0.05

Tetraethylammonium hydroxide/SiO from about 0.08

H O/tetraethylammonium hydroxidefrom about 80 to about 200 Thereafter,the crystals are separated from the liquid and recovered. Typicalreaction conditions consist of heating the foregoing reaction mixture toa temperature of from about 100 C. to 175 C. for a period of time offrom about six hours to 60 days. A more preferred temperature range isfrom about 150 to 175 C. with the amount of time at a temperature insuch range being from about 12 hours to 8 days.

The digestion of the gel particles is carried out until crystals form.The solid product is separated from the reaction medium, as by coolingthe whole to room temperature, filtering, and water washing.

The foregoing product is dried, e.g., at 230 F., for from about 8 to 24hours. Of course, milder conditions may be employed if desired, e.g.,room temperature under vacuum.

ZSM-S is prepared utilizing materials which supply the appropriateoxide. Such compositions include sodium aiuminate, alumina, sodiumsilicate, silica hydrosol, silica gel, silicic acid, sodium hydroxideand tetraethylammonium hydroxide. It will be understood that each oxidecomponent utilized in the reaction mixture can be supplied by one ormore initial reactants and they can be mixed together in any order. Forexample, sodium oxide can be supplied by an aqueous solution of sodiumhydroxide, or by an aqueous solution of sodium silicate,tetraethylammonium cation can be supplied by the bromide salt. Thereaction mixture can be prepared either batchwise or continuously] Thezeolites used in the instant invention can have the original cationsassociated therewith replaced by a wide variety of other cationsaccording to techniques well known in the art. Typical replacing cationswould include hydrogen, ammonium and metal cations including mixtures ofthe same. Of the replacing metallic cations, particular preference isgiven to cations of metals such as rare earth metals, manganese,calcium, as well as metals of Group II of the Periodic Table, e.g.,zinc, and Group VIII of the Periodic Table, e.g., nickel.

Typical ion exchange techniques would be to contact the particularzeolite with a salt of the desired replacing cation or cations. Althougha wide variety of salts can be employed, particular preference is givento chlorides, nitrates and sulfates.

Representative ion exchange techniques are disclosed in a wide varietyof patents including United States 3,140,249; United States 3,140,251;and United States 3,140,253.

Following contact with the salt solution of the desired replacingcation, the zeolites are then preferably washed with water and dried ata temperature ranging from 150 F. to about 600 F. and thereaftercalcined in air or other inert gas at temperatures ranging from about500 F. to 1500 F. for periods of time ranging from 1 to 48 hours ormore. It has been further found in accordance with the invention thatcatalysts of improved selectivity and having other beneficial propertiesin some hydrocarbon conversion processes such as catalytic cracking areobtained by subjecting the zeolite to treatment with steam at ele vatedtemperatures ranging from 800 F. to 1500 F. and preferably 1000 F. and1400 F. The treatment may be accomplished in atmospheres of steam of anatmosphere consisting of steam and a gas which is substantially inert tothe zeolites.

A similar treatment can be accomplished at lower temperatures andelevated pressures, e.g., 350-700 F. at 10 to about 200 atmospheres. Thezeolites can also be used in intimate combination with a hydrogenatingcomponent such as tungsten, vanadium, molybdenum, rhenium, nickel,cobalt, chromium, manganese, or a noble metal such as platinum orpalladium where a hydrogenation/ dehydrogenation function is to beperformed, i.e., shape selective hydrocracking. Such component can beexchanged into the composition, impregnated therein or physicallyintimately admixed therewith. Such component can be impregnated in oronto zeolite such as, for example, by, in the case of platinum, treatingthe zeolite with a platinum metal-containing ion. Thus, suitableplatinum compounds include chloroplatinic acid, platinous chloride andvarious compounds containing the platinum ammine complex.

The compounds of the useful platinum or other metals can be divided intocompounds in which the metal is present in the cation of the compoundand compounds in which it is present in the anion of the compound. Bothtypes of compounds which contain the metal in the ionic state can beused. A solution in which platinum metals are in the form of a cation orcationic complex, e.g., Pt(NH ).;Cl is particularly useful.

Prior to use, the zeolites should be dehydrated at least partially. Thiscan be done by heating to a temperature in the range of 200 to 600 C. inan inert atmosphere, such as air, nitrogen, etc. and at atmospheric orsubatmospheric pressures for between 1 and 48 hours. Dehydration canalso be performed at lower temperatures merely by using a vacuum, but alonger time is required to obtain a sufficient amount of dehydration.

As has heretofore been pointed out, the novel process of this inventionis concerned with dewaxing of hydrocarbon feedstocks. The term dewaxingas used in the specification and claims is used in its broadest senseand is intended to mean the removal of those hydrocarbons which readilysolidify (waxes) from petroleum stocks. As will be further illustratedin the specific examples, hydrocarbon feeds which can be treated includelubricating oil stocks as well as those which have a freeze point orpour point problem, i.e., petroleum stocks boiling above about 350 F.The dewaxing can be carried out at either cracking or hydrocrackingconditions.

Typical cracking conditions include a liquid hourly space velocitybetween about 0.5 and 200, a temperature between about 550 F. and 1100F., a pressure between about subatmosphcric and several hundredatmospheres.

When hydrocracking operations are carried out, operating conditionsinclude temperatures between 650 F. and 1000 F., a pressure between 100and 3000 p.s.i.g. but preferably between 200 and 700 p.s.i.g. The liquidhourly space velocity is generally between 0.1 and 10, preferablybetween 0.5 and 4 and the hydrogen to hydrocarbon mole ratio isgenerally between 1 and 20 preferably between 4 and 12.

The following examples will illustrate the best mode now contemplatedfor carrying out this invention.

EXAMPLE 1 This example will illustrate a typical preparation of zeoliteZSM-S. 22.9 grams S103 was partially dissolved in 100 ml. 2.18 Ntetrapropylammonium hydroxide by heating to a temperature of about 100C. There was then added a mixture of 3.19 grams NaAlO (comp: 42.0 wt.percent A1 30.9% Na O, 27.1% H O) dissolved in 53.8 ml. H O. Theresultant mixture had the following composition: 0.382 mole SiO 0.0131mole A1 0 0.0159 mole Na O, 0.118 mole [(CH CH CH N] O, 6.30 moles H O.The mixture was placed in a Pyrex-lined autoclave and heated at 150 C.for six days. The resultant solid product was cooled to roomtemperature, removed, filtered, washed with 1 liter H 0 and dried at 230F. A portion of this product was subjected to X-ray analysis andidentified as ZSM-S. A portion of the product was calcined at 1000 F. inair for 16 hours and the following analyses were obtained:

EXAMPLE 2 A sample of a zeolite identified as ZSM-S prepared in a manneranalogous to that set forth in Example 1 was calcined at 1000 F. in airfor 16 hours then evaluated for its ability to crack an Amal Gas Oil.The Amal Gas Oil employed was a 650850 F. boiling range waxy Amal GasOil containing 25.2 weight percent normal parafiins ranging from C s toC s.

The Amal Gas Oil was contacted with the ZSM-S at 107 WHSV, 0.56 Cat/Oilratio and 900 F. Analysis indicated that the waxy normal paraflincontent of the Amal Gas Oil had been reduced from 25.2 weight percent to4.1 weight percent, i.e. over 90% of the normal paralfins present in thecharge were cracked to lower boiling products.

EXAMPLE 3 The procedure of Example 2 was repeated with the exceptionthat a commercially available zeolite, i.e., zeolite A, which had beenbase exchanged with a lanthanum salt was used in place of the ZSM5. EvenWhen more drastic operating conditions were employed, i.e., the spacevelocity was reduced to 6 WHSV and the Cat/Oil ratio raised to 1, thenormal paratfin content could only be reduced to 16.5 weight percent.

Thus, a comparison of the results of Examples 2 and 3 shows that thenovel process of this invention permits a greater reduction in highmolecular weight waxy normal paraflins to a degree which had previouslynot been possible due to the fact that these long-chained molecules havea tendency to clog the pores of the heretofore available shape selectivemolecular sieves, thereby presenting problems in dilfusivity which leadsto less than favorable results.

EXAMPLE 4 This example will illustrate the improved results which can beobtained by the hydrocarbon processing of the instant invention due tothe fact that the catalyst employed are able to not only convert normalparaflins, but also slightly branched-chain paraflinswhich are alsodetrimental to product value.

The same waxy Amal Gas Oil used in Example 2 was subjected toconventional extraction techniques utiliz- 10 ing a 5 A. zeolite. Thisextraction was continued until substantially all the normal parafiinsfrom the Amal Gas Oil were removed. This is not a catalytic process, butmerely a conventional extraction process. The Amal Gas Oil had a pourpoint of F. and after removal of all the normal parafiins, its pourpoint was lowered to 40 F.

Another portion of the same waxy Amal Gas Oil was subjected to shapeselective cracking with a ISM-5 catalyst prepared in the manneranalogous to that set forth in Example 1. The process was carried out ata temperature of 900 F. for 10 minutes at a space velocity of 107 WHSVand a Cat/Oil ratio of 0.56. This resulted in recovery of a 650+fraction having a pour point of 5 F. with 3.6 weight percent of thenormal paratfins still remaining.

Thus, it can be seen that although the lowering of pour point isdependent on the removal of normal paratfins, such is not the completeanswer in pour point lowering. The novel process of this inventionpermits the drastic lowering of pour point even though all the normalparaflins have not been removed. While not wishing to be bound by anytheory of operation, nevertheless, it appears that the novel catalyst ofthis invention also converts slightly branched paraffins which also havea detrimental etfect on pour point.

EXAMPLE 5 A ZSM-5 zeolite was prepared in accordance to the generaltechnique set forth in Example 1; it was then contacted with a saturatedsolution of ammonium chloride in order to replace the original cationsassociated therewith and thereafter washed with water, dried andcalcined in air at about 1000 F. in order to convert it to the hydrogenform, i.e. HZSM5.

A similar treatment With an ammonium salt was carried out on a naturalcrystalline aluminosilicate identified as erionite and then these twomaterials were evaluated for their ability to selectively crack normalhexane from a mixture of normal hexane, 2,3-dimethylbutane, and benzeneat a 15:1 Hg/HC ratio, a pressure of 200 p.s.i. and a temperature of 700F. These materials were evaluated for an onstream time of 15 minutes andthree hours. The

results were as follows:

Conversion, wt. percent;

Catalysts 15 minutes 3 hours H-erinnite. 93.8 33. 7 H-ZSM-5 97. 9 97. 8

The above table clearly and dramatically illustrates the trulyremarkable and surprising results obtained utilizing the catalyst of theinstant invention. Thus, at 15 minutes the conversion between thehydrogen erionite and HZSM5 was substantially the same. This is not toosurprising since both these materials are very active crackingcatalysts. However, the results obtained after three hours are totallyunexpected in that the HZSM-5 material did not age, i.e., lose activity,as is generally the case with all other zeolites. As can be seen, theconversion with erionite dropped to 33.7% thereby showing a definiteaging whereas the conversion with H-ZSM-S was substantially unchangedafter three hours thereby illustrating the fact that the catalyst doesnot age.

EXAMPLE 6 In order to demonstrate the difference in the type of shapeselectivity obtained utilizing the catalyst of this invention as opposedto the shape selective materials of the prior art, the same waxy AmalGas Oil employed in Example 2 was subjected to shape selective crackingwith a calcined sample of ZSM-5 prepared with a crystallinealuminosilicate identified as calcium A, i.e., Linde 5A. A comparison ofthe products obtained from cracking the same material are shown in Table6.

1 l 1 2 TABLE 6 The above material was then calcined at about 100 F. for16 hours and divided into two portions. Portion A was afias(lalcisunvkt, exchanged with 100 ml. of a 0.5 N aqueous solution ofpigrcqnt p ammonium chloride at room temperature for one hour to nv rsmnconversion MA 5 form the ammonium salt. This was labeled Catalyst A1. c10,3 1, 2 Three grams of Catalyst Al was exchanged with 35 ml. of 8;: g gE a 0.5 N 2.9/1 zinc/N11 chloride soluton at 109 F. for c. 27:5 30: 53I0 four hours. The material was then washed with water and g 1 -3 fdried in air to yield a catalyst having a zinc content of 0.9 Coke 1.0 1,0 -1t 0 weight percent and a sodium content of 0.2 weight percent.

This catalyst was labeled A2.

Portion B was treated with anhydrous ammonia (100 cc. It is immediatelyobvious that the coke yield obtained per minute) at room temperature toreconstitute the NH; by the novel process of this invention isdramatically sites. This catalyst was labeled B1. Three grams ofCatalower than that obtained with a classic shape selective lyst Bl wasexchanged with a 0.5 N solution of zinc and materials of the prior art.In addition the gasoline make, ammonium chloride as above. The finishedcatalyst coni.e., the C C is considerably higher than that with thetaincd 1.2 weight percent zinc and 0.3 weight percent Calcium A-typematerials. Additionally, the classic shape sodium and was labeled B2.selective catalyst of the prior art always yields products EXAMPLE 8Wl'llCh are rich in C hydrocarbons and conversely poorer in C Chydrocarbons. As can be seen, such is not the Catalyst B2 supra, wasthen evaluated for pour point case utilizing the ZSM5 type catalysts,thereby indicatreduction of shale oil by hydroprocessing techniques. Theing that not only normal paraflins, but slightly branchedcharge stockwas a full range dehydrated shale oil havmg chain parafiins are alsoconverted. The enhanced results a pour point of about +80 F. A typicalcomposition is are believed demonstrated by the above table. shown inTable 8.

TABLE 8 Fraction, percent 11 d b t. 3 t: N C0 gu l Dawn 12 14 21 26 a321 51 36 8 compounds 5 4 4 5 5 5 7 6 0 compounds. 12 17 18 17 16 16 2219 Total 20 as 43 4s 54 42 so 61 Hydrocarbons, wt. percent:

n-Parallins 8 8 8 8 10 8 3 6 Isoparaflins plus naphthenes 7 6 4 3 3 5 5n-Olefins 10 0 11 11 0 10 a a lso-oloiins plus cyclo-olclins. 31 25 1914 12 20 5 l2 Monocycllo aromatics 0 8 6 0 5 6 2 4 Polycyclic aromaticst! 0 9 l0 7 9 2 6 Total 71 05 57 52 16 5s 20 30 The following exampleswill indicate that it is also 45 possible to obtain improved resultsutilizing hydrogenation/dehydrogenation components in association withthe ZSM5 type catalyst.

EXAMPLE 7 A ISM-5 type catalyst was prepared following the generalprocedure of Example 1. The reaction composition and characteristics ofthe finished product are shown in Table 7.

H O, wt. percent The above shale oil was contacted with Catalyst B2 at500 p.s.i.g., 4 LHSV, 800 F., and 2,000 s.c.f.s./bbl. hydrogencirculation. The results obtained showed a 97 weight percent recoveryhaving a pour point of 15 F. An analysis of the liquid product having al5 F. pour point showed that there was olefin saturation and a shift tolower boiling products resulting in increased naphtha and light fuel oilcontent with a corresponding decrease in the greater than C rangeproducts, as shown by the following table.

C5 plus liquid Charge product Cpl-naphtha 10. 0 15. 4

Light. fuel oil 16. 9 18. 2

High products- 73.1 66. 4

EXAMPLE 9 This example will illustrate the manufacture of lube oil byshape selective hydrodewaxing.

The lube oil charge stock employed had the following properties:

Gravity, API 31.9 Pour point, F. Sulfur, wt. percent 0.17 Hydrogen, wt.percent 13.23 K.V. 100 F., cs. 19.27 K.V. 210 F., cs. 3.93 Viscosityindex 108.4

13 Vacuum assay, F.:

IBP 669 696 707 30% 737 50% 766 70% 795 90% 834 95% 847 The above chargestock was subjected to hydrodewaxing with a zinc/H-ZSM-S catalystprepared in the manner set forth in Example 7 (B2), the experimentalresults as well as the various operating conditions are set forth inTable 9.

TABLE 9 Temperature, F. 700 700 650 650 LHSV 4 16 16 24 Pressure,p.s.i.g 500 500 500 11/110 mole ratio 38 38 38 Conv. wt. percent 33 30.5 25. 0 Hydrodewexud lube:

Yield, Wt. percent 67 69. 5 75.0

Pour point, F 40 +25 K.V. at, 100 F 31. 18 29.55 22. 18

K.V. at 210 F i. 85 4.75 4.15

Viscosity index 76. 9 81. (1 95. 7

From the above table, it can be seen that the instant catalyst resultedin a substantial lowering of a pour point from an original value of +85to as low as 40 F.

The above results suggest that the novel catalytic processing of thisinvention can be employed in those areas where it is desirable tohydrodewax charge stocks in order to obtain products of enhanced value.One such area would be in the preparation of automatic transmissionfluids. The above process can replace the conventional solvent dewaxingpresently employed. As another alternative, it is visualized that aparticular charge stock can be subjected to conventional solventdewaxing in order to reduce the pour point to some intermediate leveland then this product subjected to shape selective hydrodewaxing inorder to further lower the pour point. As can be seen, the novelprocessing techniques of this invention give greater flexibility to therefiner in the manufacture of commercially significant products.

EXAMPLE 10 This example will illustrate the shape selectivehydrodewaxing of lube oil stocks and will again illustrate thathydrocracking of long chain molecules can be achieved.

The charge stock employed was a mid-continent vacuum tower overheadfraction having the specifications shown in Table 10.

TABLE 10 Gravity, API 32.2 Gravity, specific 0.8644 Vacuum assay, F.:

IBP 550 5% 596 10% 630 646 50% 662 70% 684 90% 728 95% 756 Pour point,F. (D-97) +50 Flash point, F 345 Viscosity:

SUS, 100 F. 57.7 SUS, 130 F. 45.8 SUS, 210 F. 34.5 Kinematic, 100 F10.56 Kinematic, 210 F. 2.50 Viscosity index 56 Aniline No., F 182.2

This charge stock was contacted with a Zn/H-ZSM-S catalyst prepared inaccordance with the techniques set forth in Example 7 (B2). Theoperating conditions were generally mild hydrocracking conditions, i.e.,500 p.s.i., 700 F., 4 LHSV and a hydrogen to hydrocarbon moi ratio of30. The results obtained are shown in the following table.

Run time (hrs.) 2 Conversion, wt. percent 33.5 Yields, wt. percent:

Cpl-C2 1.4 C I 5.4 C 10.1 C +cracked product 16.6 Unconverted 66.5 Pourpoint, F. of unconverted product As can be seen from the above data, thenovel process of this invention resulted in a substantial lowering ofthe pour point of the product, i.e., from +50 to 85 or a 4.5 F. loweringper percent conversion. Yield was 70 weight percent of the 600 F. plusliquid product. This example clearly indicates the improved resultswhich are obtainable by the novel processing techniques of thisinvention.

EXAMPLE 1 1 This example will illustrate the preparation of a lowfreezing point high B.t.u. jet fuel prepared by the novel process ofthis invention.

A 350-500 F. Arnal-Nafoora kerosene had the following properties:

Gravity, API 48.1 Freeze point, F -27 Aromatics (FIA) vol. percent 9.1Aniline No., F 156.9

Heating value, B.t.u./lb. 18,710

TABLE 11 Gravity, API Freeze Point. F Aromatics (FIA) vol.

percent Aniline N0., F- Heating value, B.t.

The results shown in the above table illustrate the fact that the novelprocess of this invention is capable of significantly lowering thefreeze point of an Amal kerosene. It is noted, however, that the heatingvalue and aromatic content of the product fall outside the specificationfor JP-7 jet fuel.

In order to raise the heating value and lower the aromatic content, thehydrodewaxed product can be subjected to a mild hydrogenation treatment.In this connection 20 grams of the hydrodewaxed product, ml. ofcyclohexane, 11 grams of a commercial catalyst comprising reduced nickelor Kieselguhr (Harshaw Ni 0107) were charged to a 300 ml. stirringautoclave and 500 p.s.i.g. hydrogen was added. The above mixture washeated at 587-600 F. about 2 hours at which time the final pressure wasabout 1200-1300 p.s.i.g. The above procedure resulted in a 93 wt.percent recovery of a hydrogenated product which had the propertiesshown in Table 12.

15 TABLE 12 Gravity, APA 47.5 Freeze point, F. 81 Aromatics (FIA) vol.percent 4.0 Aniline No., F 179.0 Heating value, B.t.u./lb 18,835

From the above, it can be seen that the novel process of this inventionprovides a method of producing jet fuels having a low freeze point and ahigh B.t.u. content.

What is claimed is:

1. A dewaxing process for the selective cracking of straight-chainhydrocarbons and slightly branched-chain hydrocarbons from a mixture ofthe same with com pounds of dilferent molecular shapes which comprisescontacting said mixture with a crystalline aluminosilicate having anX-ray diffraction pattern as set forth in Table 1 and having poreopenings which are of a generally elliptical shape wherein the majoraxis of said ellipse has an effective size under conversion conditionsof between about 6 and 9A. units and the minor axis about 5 A. so thatsaid straight-chain and slightly branchedchain hydrocarbons are capableof entering into the internal pore structure of the aluminosilicate andbeing converted, said aluminosilicate having a composition, in terms ofoxide mole ratios, as follows:

0.91-0.22 M O :A1g03 5-100 SiO,:zH

wherein M is a cation, 11 is the valence of said cation and z is from 0to 40.

2. The process of claim 1 wherein said slightly branched hydrocarbondoes not possess a quaternary carbon atom.

3. The process of claim 1 wherein said aluminosilicate has ahydrogenation/debydrogenation function.

4. A process for dewaxing petroleum charge stocks having a boiling pointabove 350 F. which comprises contacting said charge under crackingconditions with a crystalline aluminosilicate having an X-raydiffraction pattern set forth in Table 1 so as to selectively crackstraight-chain hydrocarbons and branched-chain hydrocarbons free fromquaternary carbon atoms in their structure, said aluminosilicate havinga composition, in terms of oxide mole ratios, as follows:

0910.2 M O:Al O :5100 SlO ZZH O wherein M is a cation, 11 is the valenceof said cation, and z is from 0 to 40.

5. A dewaxing process for the selective cracking of straight-chainhydrocarbons and branched-chain hydrocarbons which are free fromquaternary carbon atoms in their structure from a mixture of the samewith cyclic compounds, and branched-chain hydrocarbons containingquaternary carbon atoms which comprises contacting said mixture with acrystalline aluminosilicate having an X-ray diffraction pattern setforth in Table 1, and a composition, in terms of oxide mole ratios, asfollows:

M2/ OIAI203IS-IOO SiOzIZHgO wherein M is a cation, 11 is the valence ofsaid cation and z is from 0 to 40.

6. A dewaxing process for the selective conversion of straight-chainhydrocarbons and branched-chain hydrocarbons free from quaternary carbonatoms from a mixture of the same with compounds of differing molecularshape which comprises contacting the same with zeolite ZSM-S undercracking conditions such that the straightchain hydrocarbons andslightly branched hydrocarbons are able to enter into the pores of theZSM-S and be cracked, said zeolite having an X-ray dillraction patternas set forth in Table 1 and a composition, in terms of oxide moleratios, as follows:

O-9iD-2 M2/ O:Al203:5100 SiOziZHgO wherein M is a cation, n is thevalence of said cation, and z is from 0 to 40.

[7. A dewaxing process for the selective conversion of straight-chainhydrocarbons and branched-chain hydrocarbon free from quaternary carbonatoms from a mixture of the same with compounds of differing molecularshape which comprises contacting the same with zeolite ZSM-8 underconversion conditions such that the straightchain hydrocarbons andslightly branched hydrocarbons are able to enter into the pores of theZSM-8 and be cracked, said zeolite having an X-ray difiraction patternas set forth in Table 4 and a composition, in terms of oxide moleratios, as follows:

0910.2 M2/ O:A1g03:5100 SlO IZH O wherein M is a cation, n is thevalance of said cation, and z is from 0 to 40.]

8. The process of claim 5 wherein the dewaxing is carried out in thepresence of added hydrogen and the aluminosilicate has ahydrogen/dehydrogenation component associated therewith.

9. The process of claim 6 wherein the dewaxing is carried out in thepresence of added hydrogen and the aluminosilicate has ahydrogenation/dehydrogenation component associated therewith.

[10. The process of claim 7 wherein the dewaxing is carried out in thepresence of added hydrogen and the zeolite has ahydrogenation/dehydrogenation component associated therewith] 11. Theprocess of claim 4 wherein the dewaxing is carried out in the presenceof added hydrogen and the aluminosilicate has ahydrogenation/dehydrogenation component associated therewith.

12. The process of claim I wherein said mixture is crude oil.

13. The process of claim I wherein said mixture is full range dehydratedshale oil.

14. The process of claim I wherein said mixture is a lube oil stock.

15. The process of claim I wherein said crystalline aluminosilicate isZSM-S type zeolite.

16. The process of claim 5 wherein said crystalline aluminosilicate isZSM-5 zeolite.

References Cited The following references, cited by the Examiner, are ofrecord in the patented file of this patent or the original patent.

UNITED STATES PATENTS 3,438,887 4/1969 Morris et a]. 208-87 3,385,7815/1968 Harnner et al 20859 3,575,846 4/1971 Harnner et al 208Il13,492,218 1/ 1970 Collier et al. 208-27 3,516,925 6/1970 Lawrance et a1208-111 3,539,498 11/1970 Morris et a1. 208-111 FOREIGN PATENTS1,167,869 10/1969 Great Britain 208-27 DELBERTE E. GANTZ, PrimaryExaminer G. E. SCHMITKONS, Assistant Examiner U.S. Cl. X.R.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT NO. Re. 28,398

DATED April 22, 1975 N i Y h s 1 J. L k1 'NVENTOW and ee iliae aeeweedIt is certified that error appears rn the ab0ve-identifted patent andthat said Letters Patent are hereby corrected as shown below:

Column 12, line 1 "100" should be --1000-- Column 5, line 2 Last word"deserved" should be --observed-- Signed and Scaled this fourreenth D ayof October 1975 [SEAL] I Arrest:

RUTH C. MASON C. MARSHALL DANN Arrestmg ()fj'r'rer (ummrsnurwr u]Pure/us and Trademark-x

0.9$0.2 M2/NO:AL2O3:5-100 SIO2:ZH2O
 1. A DEWAXING PROCESS FOR THESELECTIVE CRACKING OF STRAIGHT-CHAIN HYDROCARBONS AND SLIGHTLYBRANCHED-CHAIN HYDROCARBONS FROM A MIXTURE OF THE SAME WITH COMPOUNDS OFDIFFERENT MOLECULAR SHAPES WHICH COMPRISES CONTACTING SAID MIXTURE WITHA CRYSTALLINE ALUMINOSILICATE HAVING AN X-RAY DIFFRACTION PATTERN AS SETFORTH IN TABLE 1 AND HAVING PORE OPENINGS WHICH ARE OF A GENERALLYELLIPTICAL SHAPE WHEREIN THE MAJOR AXIS OF SAID ELLIPSE HAS AN EFFECTIVESIZE UNDER CONVERSION CONDITIONS OF BETWEEN ABOUT 6 AND 9A. UNITS ANDTHE MINOR AXIS ABOUT 5 A. SO THAT SAID STRAIGHT-CHAIN AND SLIGHTLYBRANCHEDCHAIN HYDROCARBONS ARE CAPABLE OF ENTERING INTO THE INTERNALPORE STRUCTURE OF THE ALUMINOSILICATE AND BEING CONVERTED, SAIDALUMINOSILICATE HAVING A COMPOSITION, IN TERMS OF OXIDE MOLE RATIOS, ASFOLLOWS: